It is known that polymerization devices such as, for example, light polymerization devices, are used for polymerizing restoration materials such as, for example, materials in dental products, and require an exact output of the polymerization radiation in order to ensure a reliable and reproducible restoration result. It is known that a deviation from the pre-set irradiation value can lead to significant degradation of restoration results. Thus, an overly intensive energy irradiation leads to an overly strong complete hardening and, consequently, edge crack formation, while an overly minimized energy irradiation leads to an incomplete hardening so that there remains a not-polymerized monomer portion in the dental restoration.
Polymerization devices for dental practices are frequently operated at various radiation frequency spectrums. Thus, it is known to integrate thermal sources as well as light sources in the hood of a polymerization device. A solution of this type is disclosed, for example, in U.S. Pat. No. 5,922,605.
Various measures have been suggested for calibrating the light output of halogen light sources. Thus, it has been suggested to dispose a light sensor at a precisely determined distance from the light source with the light sensor having a pre-determined spectral sensitivity. The output signal of the light sensor should then indicate the light intensity of the light source reaching the location of interest.
A solution of this type requires, to be sure, a corresponding switch connection for the outputs of the light sensor. On the other hand, a mobile wiring arrangement for a light sensor—which must then be removed in operation—when combined with a corresponding switch, is significantly expensive and, also, is susceptible to errors. Care must be taken with such an arrangement that, for example, it is not overlooked, during the light measurement operation, that the thermal source is inadvertently actuated as otherwise the light sensor will, in such a situation, be subjected to damage.
Current combined thermal and light hardening devices emit, to a large extent, infrared radiation—that is, thermal radiation—in order to effect the polymerization. This means, on the one hand, that the infrared radiation must be at least as significant as the light radiation, if not even more significant. On the other hand, in connection with the construction of such combined thermal and light polymerization devices, it has consistently been assumed that a commercially available thermostat is adequate for a workably precise determination of the temperature. A thermostat of this type can be configured in classic manner with the use of a bimetallic strip, or configured in electronic configuration—that is, via the use of a PTC—or, optionally, an NTC—, resistance element. Such thermostats are calibrated and it is assumed that the precision during the operational life of the device is adequate.
On the other hand, the materials used for the production of temperature sensors typically exhibit a certain degree of aging. In order to compensate for such aging, it is recommended that a re-calibration be performed. For example, a mobile electronic and calibrated temperature calibration unit provided with a sensor, which is mounted on the tip of a probe, is inserted in the polymerization device between the base and hood thereof in order to undertake a re-calibration. Such a re-calibration arrangement can, however, for all practical purposes, only be provided by the producer of the polymerization device, as the customers of the polymerization devices would not be motivated to procure such a significantly expensive electronic temperature calibration unit.